fix(deps): update dependency ejs to v5

Author: renovate[bot]

package.json

@@ -39,7 +39,7 @@
   "dependencies": {
     "@google/genai": "^1.11.0",
     "dotenv": "^17.0.0",
-    "ejs": "^3.1.10",
+    "ejs": "^5.0.0",
     "express": "^5.1.0",
     "express-session": "^1.18.1",
     "express-ws": "^5.0.2",